I can't let this go. In an interview on ZDNet Don Box states:
"We have to do something to make it (HTTP) less important," said Box. "If we rely on HTTP we will melt the Internet. We at least have to raise the level of abstraction, so that we have an industry-wide way to do long-running requests--I need a way to send a request to a server and not the get result for five days."
Uhh, it's called email Don, specifically SOAP via email. There's even an RFC for it.